Commutator



May 15, 1928. 1,669,806

R.B.BRET2 GOMMUTATOR Filed Nov. 13. 1925 44,7 ma?, Irrwmf Patented May 15, 1928.

UNITED STATES PATENT OFFICE,

ROBERT IB. BRETZ, OF EL RENO, OKLAHOMA, ASSIGNOR OF ONE-HALF TO ARTHUR C. SCHROEDER, OF SYRACUSE, NEW YORK.

COMMUTATOR.

Application filed November 13, 1925.

rIhis invention relates to an improved commutator particularly designed for use in connection with Ford engines, and seeks, among other objects, to provide a device of this character wherein the usual troubles of imperfect circuit closing and consequent time lag, shorting, oil fouling, and premature failure as now commonly experienced in connection with prevalent commutators for Ford engines, will be eliminated.

The invention seeks, as a further object, to provide a commutator wherein the primary ignition circuit will not only be closed through the timer shaft, as in ordinary com- V mutators, but will also be closed directly through the engine block.

Still another object of the invention is to provide a commutator wherein the brush employed will, at each of the energized contacts of the device, function to bridge the gap between the contact and the electrically grounded base of the device, as the brush moves onto the contact, and will likewise function to bridge the gap between each contact and the base as the brush moves olf the contact, and wherein the brush will be constantly grounded to the base so that arcing of the current as well as pitting and burning of the contacts and brush will be minimized.

A further object of the invention is to provide a device wherein the brush will be confined between confronting electrically grounded raceways to coact therewith and wherein the brush will be mounted to revolve about its own axis against said raceways so that the contact surfaces of the brush will be maintained bright and clean.

And the invention seeks, as a still further object, to provide a device wherein the brush will be mounted to float upon the rotor of the commutator so that movement of the rotor, due to any end play or lateral play in the timer shaft, will not dislocate the brush.

Other objects of the invention not specifically mentioned in the foregoing will appear during the course of the following description.

In the accompanying drawings:

Figure 1 is a perspective view of my improved commutator showing the parts disassembled but in proper relative position.

Figure 2 is a vertical sectional view showing the device applied.

Figure 3 is a detail sectional view on the Serial No. 68,903.

line 3 3 of Figure 2, looking in the direction indicated by the arrows.

Figure et is a diagrammatic view showing the commutator in connection with the primary and secondary ignition circuits of a Ford engine.

In carrying the invention into effect, I employ a circular base having a bottom wall 10, and extending rearwardly from said wall is a surrounding skirt 11 while a peripheral flange 12 extends forwardly from said wall. Integral with the wall 10 are quadrantly spaced radial channels 13 connected at their inner ends by an annular flange 1a defining a central opening' through the base, and formed in the flange 12 at the outer ends of said channels are notches 15. As shown in Figure 2, the cent-ral opening ofthe base is of a diameter to freely receive the usual Ford timer shaft, as conventionally illustrated at 16, while the skirt 11 of the base is of a diameter to snugly fit within the usual centering flange 17 on the transmission gear case 18 of the engine. The base is preferably of bronze. although brass, copper, or any other suitable material may be employed, and projecting from the base at one side thereof is a preferably integral arm 19 to which the usual control rod is connected for rotating the base to advance and retard the instant of firing.

Lying in the channels 13 of the base are trough-shaped insulating bushings 20, and extending through said bushings and through the bottom walls of the channels 13, as particularly seen in Figure 2, are sleeves 21 locking the bushings in position. Lying in the bushings 2O are substantially semi-cylindrical contacts 22 which are freely accommodated through the notches 15 of the flange 12 to project radially with respect to the base, and mounted upon the outer ends of said contacts are binding screws 23 for connecting the usual circuit wires thereto. Fitting snugly within the fiange 12 of the base to overlie the contacts 22 is an insulating ring 2d and extending through said ring and through the contacts are insulating locking pins 25 accommodated by the sleeves 21 for securing the contacts againstendwise movement. Over-lying the insulating ring 2e is a metal clamping ring 26, and extending through said rings and through the wall 10 of the base, as seen in Figure 3, are bolts or other fastening devices 27 tightly binding the contact-s in position. Thus, as will be perceived, the contacts are clamped between thebushings 20 and the ring 24 and are thus effectively insulated with respectfto .the base Mounted upon-the forward endofthe timer shaft 16 is a rotor including` a sleeve- 29=xwhich`4 sliidably lits over-fthe shaft, and formed in' said sleeve is a notch 30'to acL coinmodate the usual 4locking pin 3l. Eri-.1

circling the sleeve to overlie the headof said pin is ythe usual f retaining cap 32,H and screwed on theforward end of the shaft ,is i

the customary nut 33 securing Vthe rotor vupon the shaft. Projecting radial-ly from the.'`

sleeve 29 ofthe rotor is an arm' 3i, and mounted to'float upon said arm'is ajbrush 35 which, as shown in Figure 3, is composed tions apart.

opening to freely receive the larger section of'the brush and preferablythe rotor and the base."

base' is a .cap 37 which rests `against-the y clampingjring 26. and is stepped to define anannular raceway 38 from'which rises an axially disposed.` dome 39.4 The donieis of f' more,l attentionis directedto the fact :thatrsince the bruslr is loosely inounted-'onftherio an internal diameter to yfreely yaccomiiioda-.te the forward end ofthe shaft 16 and associated parts thereon, and 1 bearing at one end against the dome is the usual spring'arni 4i-O" clamping the capand base in assembled relation aswell as'holding the basev seated" within the fiange 17 ,of the timinggear case of the engine.v rl`h`us, as will'be seen, the.V brush is confined betweentheraceways 2S" and :38 to seat iiat `at its'ends thereagainst while the spring 36is compressed vfor holding the ends of the brush ,in firm contactl `with saidvraseways i As willenow be readily-understood in view of Vthe foregoing, the brush 35 will, as the timer Yshaft 16 rotates, be Vcaused kto ridev at its in neijMend over the .contacts-,22 forzclosinga circuit through'said `contacts successively, and in Figure 4C yofthe drawings, VI have L diagrammatically shown the comniutae tator in connection with/theusual p 1imary and secondary circuits of a `Fordignitionl system.V Extendingffrom the engine magneto -to 'connect -vvith corresponding terminals-offthepriniary lwindings. of the usual coils, is a wire 4l, and connectingthe op posite terminals kof said Win-dingswvith the several contacts 22 are wires 42, while Wires a3* connect the secondary windings ofi said coils with the several sparlrplugs, indicated atea.- Thus, as the brush travels over each of the contacts 22, a circuit-.througlithe 7o primary; winding-of i the corresponding coil is closed through the wire 4l and one of the wires. l2 so that current is caused to flow through the secondary winding of said coil and through one-ofthecwires 43 and a cor- 75 responding spark plug to eiect ignition.

As will; be perceived, the brush' 35v ishpermanently grounded at its outer-endthrough" the raceway 33, cap 37, and the base"of*the commutator, direct to the engine block whilevan the inner end of thebrush' is likewisedirectl ly grounded 'intermittently' to the engine block: throughfthe raceway- 28 'oftthedoaseL Accordingly, as the inner'end of fthevbiush'` moves onto any one of the cont-acts 22,` ass suggested in Figure 3, a circuit will be closed* through the outer'end ofthe brush tothe raceway 3Sand thence through thetcap'y and' 1 base to the engine block, while .at thewinnery of tubular telescopic sections closed Lat "their outerends'and slidably fitti-ngone within the` other to house a spring 36pressing the sec-A As will'be observed, the arm. 34 is formed near its outer end with an cuit through the Vinner end 'ofthe brush; the *es later raceway, and through'the baselO'to the brush areformed of the saine material asv block. Lilie conditions will', of course,-'prem vail as the brushl'leaves-each contact.: The brush thus provides a groundedV doublecon-z tact connection in thecircuit Vand 'by'.bridg ico ing the circuit at the inner end of the brush;

it has been found that arcingbur'ning,and pitting` of the parts is minimized. Further--Y arm 34 of the rotor, the ends ofwthebrush will, as said 'armrevolves;y frictionally"coactpl with the raceways for causing the brush to' lro=y tate about its own axis. This individualrota; tion of the brush will, of course, be entirely au# lio toniatic so that' the end surfaces `of the brush will be constantly smoothed, iiattened, and'vl cleaned by the grinding-action'thereon set upby the rotationof the brush; while any given points on 'said surfaces willlcoincidently be #'115 caused to change their `radial'position in the circular tracks on the .ra'ceways of the'biuShA-f ends toA prevent scoring vlof Vsaid ,fraceways/ Thus, assuming that a crater shouldfbe" formed ony the innerfend of the -brushthe crater would be immediately; ground tiff while, due to the local circular travel im-" pai-ted to the crater by the individual rotay` tion Y of the brush, the `crater would' bepijevented from scratching a circular groove in the raceway-28- Lilrewise,fshould'fany ffo`r`` eign substance, such forfinstance as-aparf ticleof dust, become disposed beneath 'either end of the brush, such substance would. beAv Vimmediatelythrown out rbytheindividual rotation of the brush. The brush will thus always function to effectively close the low tension circuit through the usual induction coils of the ignition system so that the time lag, which would otherwise be experienced through faulty functioning of said coils, will be avoided.

Since the raceway 28 faces forwardly at a right angle to the axis of the timer shaft, oil fouling of this raceway will be great-ly minimized and even though the raeeway 38 faces inwardly, it has been found that, due to the protected position of this latter raceway, in parallel relation to the former raceway, oil fouling of the latter raceway is also largely minimized. Either raceway may be readily cleaned simply by removing the cap 37, and should either of the raceways become worn, said raceways may be readily turned to a flat surface, it being observed that in order to thus turn the raceway 28, removal of the contacts 22 and associated parts is unnecessary. The device will thus provide almost a permanent accessory, save perhaps an occasional renewal of the brush.

As is well known, a certain amount of side and end play often develops in the timer shaft of a Ford engine and since, in the usual commutator, the brush is rigidly connected with the timer shaft, such side and end play directly aects the functioning of the commutator. However, in the present device, side play of the timer shaft will only vary the path of travel of the brush between the raceways and, due to the loose mounting of the brush, cannot affect the action thereof. Likewise, when the shaft shifts endwise, the brush will remain in engagement with both raceways while the arm 34 will slide along the brush to accommodate the endwise movement of the shaft. I thus provide a very efficient construction for the purpose set forth and while I have illustrated and described the preferred embodiment of my invention in connection with a Ford engine, still, as will be appreciated, various changes in structural details may be made while the device may also be easily adapted for use in connection with engines of other makes and l do not, therefore, wish to be limited in these respects but reserve the right to all variations and modifications of the invention as may fall within the spirit of the appended claims.

Having thus described the invention, what I claim is:

l. A cominutator including a base having a raceway, contacts located in said raceway, insulating means seating the contacts and insulating said contacts with respect to the raceway, insulating means overlying said contacts, a ring overlying the last-mentioned insulating means and clamping the contacts between said two insulating means, and circuit closing means movable over said race'- way to successively cooperate with said contacts.

2. The combination with an engine block and a timer shaft, of a commutator operatively associated with said shaft and including spaced raceways, one of which is electrically grounded to the engine block, a contact located in one of said raceways, and a brush consisting of tubular sections telescopically fitted together and yieldably held extended to coact with said raceways and driven by the timer shaft for intermittently closing a circuit through said Contact, said brush' having constant ground connection through said grounded raceway with the engine block.

3. A commutator including a base provided wi'th a raceway electrically grounded, a contact located in said raceway but insulated therefrom, a cap mating with the base and provided with a raceway electrically grounded through said cap and base, an arm provided with an opening, an a lineally eX- pansiblc brush slidably fitting through said opening and confined between said raceways to coact therewith, said brush being movable for intermittently closing a circuit through said contact, said brush having constant ground connection through the latter raceway.

In testimony whereof I affix my signature.

ROBERT B. BRETZ. [Ls] 

